/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Collections;
using System.Text;
using System.IO;
using PdfSharp.Internal;
using System.Collections.Generic;

namespace PdfSharp.Pdf.Advanced
{
  /// <summary>
  /// Represents a PDF resource object.
  /// </summary>
  public sealed class PdfResources : PdfDictionary
  {
    // Resource management works roughly like this:
    // When the user creates an XFont and uses it in the XGraphics of a PdfPage, then at the first time
    // a PdfFont is created and cached in the document global font table. If the user creates a new
    // XFont object for an exisisting PdfFont, the PdfFont object is reused. When the PdfFont is added
    // to the resources of a PdfPage for the first time, it is added to the page local PdfResourceMap for 
    // fonts and automatically associated with a local resource name.

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfResources"/> class.
    /// </summary>
    /// <param name="document">The document.</param>
    public PdfResources(PdfDocument document)
      : base(document)
    {
      Elements[Keys.ProcSet] = new PdfLiteral("[/PDF/Text/ImageB/ImageC/ImageI]");
    }

    public PdfResources(PdfDictionary dict)
      : base(dict)
    {
    }

    /// <summary>
    /// Adds the specified font to this resource dictionary and returns its local resource name.
    /// </summary>
    public string AddFont(PdfFont font)
    {
      string name = (string)this.resources[font];
      if (name == null)
      {
        name = NextFontName;
        this.resources[font] = name;
        if (font.Reference == null)
          this.Owner.irefTable.Add(font);
        Fonts.Elements[name] = font.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified image to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddImage(PdfImage image)
    {
      string name = (string)this.resources[image];
      if (name == null)
      {
        name = NextImageName;
        this.resources[image] = name;
        if (image.Reference == null)
          this.Owner.irefTable.Add(image);
        XObjects.Elements[name] = image.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified form object to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddForm(PdfFormXObject form)
    {
      string name = (string)this.resources[form];
      if (name == null)
      {
        name = NextFormName;
        this.resources[form] = name;
        if (form.Reference == null)
          this.Owner.irefTable.Add(form);
        XObjects.Elements[name] = form.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified graphics state to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddExtGState(PdfExtGState extGState)
    {
      string name = (string)this.resources[extGState];
      if (name == null)
      {
        name = NextExtGStateName;
        this.resources[extGState] = name;
        if (extGState.Reference == null)
          this.Owner.irefTable.Add(extGState);
        ExtGStates.Elements[name] = extGState.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified pattern to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddPattern(PdfShadingPattern pattern)
    {
      string name = (string)this.resources[pattern];
      if (name == null)
      {
        name = NextPatternName;
        this.resources[pattern] = name;
        if (pattern.Reference == null)
          this.Owner.irefTable.Add(pattern);
        Patterns.Elements[name] = pattern.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified pattern to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddPattern(PdfTilingPattern pattern)
    {
      string name = (string)this.resources[pattern];
      if (name == null)
      {
        name = NextPatternName;
        this.resources[pattern] = name;
        if (pattern.Reference == null)
          this.Owner.irefTable.Add(pattern);
        Patterns.Elements[name] = pattern.Reference;
      }
      return name;
    }

    /// <summary>
    /// Adds the specified shading to this resource dictionary
    /// and returns its local resource name.
    /// </summary>
    public string AddShading(PdfShading shading)
    {
      string name = (string)this.resources[shading];
      if (name == null)
      {
        name = NextShadingName;
        this.resources[shading] = name;
        if (shading.Reference == null)
          this.Owner.irefTable.Add(shading);
        Shadings.Elements[name] = shading.Reference;
      }
      return name;
    }

    /// <summary>
    /// Gets the fonts map.
    /// </summary>
    internal PdfResourceMap Fonts
    {
      get
      {
        if (this.fonts == null)
          this.fonts = (PdfResourceMap)Elements.GetValue(Keys.Font, VCF.Create);
        return this.fonts;
      }
    }
    PdfResourceMap fonts;

    /// <summary>
    /// Gets the external objects map.
    /// </summary>
    internal PdfResourceMap XObjects
    {
      get
      {
        if (this.xObjects == null)
          this.xObjects = (PdfResourceMap)Elements.GetValue(Keys.XObject, VCF.Create);
        return this.xObjects;
      }
    }
    PdfResourceMap xObjects;

    // TODO: make own class
    internal PdfResourceMap ExtGStates
    {
      get
      {
        if (this.extGStates == null)
          this.extGStates = (PdfResourceMap)Elements.GetValue(Keys.ExtGState, VCF.Create);
        return this.extGStates;
      }
    }
    PdfResourceMap extGStates;

    // TODO: make own class
    internal PdfResourceMap ColorSpaces
    {
      get
      {
        if (this.colorSpaces == null)
          this.colorSpaces = (PdfResourceMap)Elements.GetValue(Keys.ColorSpace, VCF.Create);
        return this.colorSpaces;
      }
    }
    PdfResourceMap colorSpaces;

    // TODO: make own class
    internal PdfResourceMap Patterns
    {
      get
      {
        if (this.patterns == null)
          this.patterns = (PdfResourceMap)Elements.GetValue(Keys.Pattern, VCF.Create);
        return this.patterns;
      }
    }
    PdfResourceMap patterns;

    // TODO: make own class
    internal PdfResourceMap Shadings
    {
      get
      {
        if (this.shadings == null)
          this.shadings = (PdfResourceMap)Elements.GetValue(Keys.Shading, VCF.Create);
        return this.shadings;
      }
    }
    PdfResourceMap shadings;

    // TODO: make own class
    internal PdfResourceMap Properties
    {
      get
      {
        if (this.properties == null)
          this.properties = (PdfResourceMap)Elements.GetValue(Keys.Properties, VCF.Create);
        return this.properties;
      }
    }
    PdfResourceMap properties;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextFontName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/F{0}", this.fontNumber++))) { }
        return name;
      }
    }
    int fontNumber;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextImageName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/I{0}", this.imageNumber++))) { }
        return name;
      }
    }
    int imageNumber;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextFormName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/Fm{0}", this.formNumber++))) { }
        return name;
      }
    }
    int formNumber;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextExtGStateName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/GS{0}", this.ExtGStateNumber++))) { }
        return name;
      }
    }
    int ExtGStateNumber;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextPatternName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/Pa{0}", this.PatternNumber++))) ;
        return name;
      }
    }
    int PatternNumber;

    /// <summary>
    /// Gets a new local name for this resource.
    /// </summary>
    string NextShadingName
    {
      get
      {
        string name;
        while (ExistsResourceNames(name = String.Format("/Sh{0}", this.ShadingNumber++))) ;
        return name;
      }
    }
    int ShadingNumber;

    /// <summary>
    /// Check whether a resource name is already used in the context of this resource dictionary.
    /// PDF4NET uses GUIDs as resource names, but I think this weapon is to heavy.
    /// </summary>
    internal bool ExistsResourceNames(string name)
    {
      // TODO: more precise: is this page imported and is PageOptions != Replace
      // BUG: 
      //if (!this.Owner.IsImported)
      //  return false;

      // Collect all resouce names of all imported resources.
      if (this.importedResourceNames == null)
      {
        this.importedResourceNames = new Hastable();

        if (Elements[Keys.Font] != null)
          Fonts.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.XObject] != null)
          XObjects.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.ExtGState] != null)
          ExtGStates.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.ColorSpace] != null)
          ColorSpaces.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.Pattern] != null)
          Patterns.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.Shading] != null)
          Shadings.CollectResourceNames(this.importedResourceNames);

        if (Elements[Keys.Properties] != null)
          Properties.CollectResourceNames(this.importedResourceNames);
      }
      return this.importedResourceNames.ContainsKey(name);
      // This is superfluous because PDFsharp resource names cannot be double.
      // this.importedResourceNames.Add(name, null);
    }

    /// <summary>
    /// All the names of imported resources.
    /// </summary>
    Hastable importedResourceNames;

    /// <summary>
    /// Maps all PDFsharp resources to their local resource names.
    /// </summary>
    readonly Hastable resources = new Hastable();

    /// <summary>
    /// Predefined keys of this dictionary.
    /// </summary>
    public sealed class Keys : KeysBase
    {
      /// <summary>
      /// (Optional) A dictionary that maps resource names to graphics state 
      /// parameter dictionaries.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string ExtGState = "/ExtGState";

      /// <summary>
      /// (Optional) A dictionary that maps each resource name to either the name of a
      /// device-dependent color space or an array describing a color space.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string ColorSpace = "/ColorSpace";

      /// <summary>
      /// (Optional) A dictionary that maps each resource name to either the name of a
      /// device-dependent color space or an array describing a color space.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string Pattern = "/Pattern";

      /// <summary>
      /// (Optional; PDF 1.3) A dictionary that maps resource names to shading dictionaries.
      /// </summary>
      [KeyInfo("1.3", KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string Shading = "/Shading";

      /// <summary>
      /// (Optional) A dictionary that maps resource names to external objects.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string XObject = "/XObject";

      /// <summary>
      /// (Optional) A dictionary that maps resource names to font dictionaries.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string Font = "/Font";

      /// <summary>
      /// (Optional) An array of predefined procedure set names.
      /// </summary>
      [KeyInfo(KeyType.Array | KeyType.Optional)]
      public const string ProcSet = "/ProcSet";

      /// <summary>
      /// (Optional; PDF 1.2) A dictionary that maps resource names to property list
      /// dictionaries for marked content.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional, typeof(PdfResourceMap))]
      public const string Properties = "/Properties";

      /// <summary>
      /// Gets the KeysMeta for these keys.
      /// </summary>
      internal static DictionaryMeta Meta
      {
        get
        {
          if (Keys.meta == null)
            Keys.meta = CreateMeta(typeof(Keys));
          return Keys.meta;
        }
      }
      static DictionaryMeta meta;
    }

    /// <summary>
    /// Gets the KeysMeta of this dictionary type.
    /// </summary>
    internal override DictionaryMeta Meta
    {
      get { return Keys.Meta; }
    }
  }
}
